2-Amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol and a pharmaceutically acceptable acid addition salt thereof are known to be useful as a suppressant of rejection in organ or bone marrow transplantation or as a therapeutic agent of various autoimmune diseases such as psoriasis, Beh.cedilla.et's disease and the like and rheumatic diseases, as described in, for example, WO94/08943.
The above-mentioned WO94/08943 discloses a preparation of said compound as an injection, and the solubilizers therefor disclosed are polyethylene glycol and ethanol. Nevertheless, polyethylene glycol shows undesirable effects such as local irritation and hemolysis, and the use thereof will be limited. In addition, ethanol is unapplicable to injections due to the local irritation it causes.
When the above-mentioned compound, particularly 2-amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol hydrochloride (hereinafter sometimes referred to as the present compound throughout the specification) is dissolved in distilled water to make a liquid preparation, the liquid preparation obtained problematically causes hemolysis and local irritation. Even a liquid preparation containing the present compound and an isotonizing agent, such as sodium chloride, as an additive ordinarily employed for a liquid preparation, such as an injection or an eye drop, could not reduce hemolysis and local irritation, and the preparation was not satisfactory.
Japanese Patent Examined Publication No. 48485/1975 discloses that a lecithin, particularly egg yolk lecithin, dose not show hemolysis. However, this publication does not teach that lecithin relieves hemolysis by the active ingredient compound. Further, Japanese Patent Unexamined Publication No. 340525/1994 discloses an eye drop characteristically containing vitamin A, hydrogenated lecithin and nonionic surfactant at a particular ratio in order to stabilize vitamin A and relieve irritation to the eye. This publication describes that, since a nonionic surfactant to be added to vitamin A, which is the active ingredient, causes irritation to the eye and, in order to relieve the irritation, hydrogenated lecithin is added at a ratio of 0.1 to 1 part per part of vitamin A, and 0.01 to 1 part per part of nonionic surfactant.